Setting up Inventory Control after using the system for years

Hi. I have set up the quantities by adjusting old quantities with production and delivery amounts. The Inventory Report by Location gives the correct amounts but the Inventory Quantity Report gives different figures. How can that be?

Also I would like to produce separate reports of quantities by product produced, received and despatched. Is it possible?

Many thanks to whoever answers.

the Inventory Quantity Summary reports between two specified dates while the Inventory Quantity by Location reports as at a particular date.